Galvanic Vestibular Stimulation Modulates the Electrophysiological Response During Face Processing

Although galvanic vestibular stimulation (GVS) is known to affect the speed and accuracy of visual judgments, the underlying electrophysiological response has not been explored. In the present study, we therefore investigated the effect of GVS on the N170 event-related potential, a marker commonly associated with early visual structural encoding. To elicit the waveform, participants distinguished famous from non-famous faces that were presented in either upright or inverted orientation. Relative to a sham, stimulation increased the amplitude of the N170, and also elevated power spectra within the delta and theta frequency bands, components that have likewise been associated with face processing. This study constitutes the first attempt to model the effects of GVS on the electrophysiological response, and more specifically, indicates that uni-sensory visual processes linked to object construction are influenced by vestibular information. Given that reductions in the magnitude of both the N170 event-related potential and delta/theta activity accompany certain disease states, GVS may provide hitherto unreported therapeutic benefit.